WO2022098618A1

WO2022098618A1 - Substrates with improved electrostatic performance

Info

Publication number: WO2022098618A1
Application number: PCT/US2021/057661
Authority: WO
Inventors: Hideki Kobayashi; Yasuyuki Mizushima; Hisanori NAKANISHI
Original assignee: Corning Incorporated
Priority date: 2020-11-06
Filing date: 2021-11-02
Publication date: 2022-05-12
Also published as: JP2023549138A; CN116615396A; KR20230104183A; TW202235395A

Abstract

A substrate includes a glass sheet and a deposition layer deposited on a major surface of the glass sheet. The deposition layer includes inorganic particles and imparts a surface roughness on the major surface ranging from about 0.4 nanometers to about 50 nanometers.

Description

SUBSTRATES WITH IMPROVED ELECTROSTATIC PERFORMANCE

Cross Reference to Related Applications

[0001] This application claims priority under 35 U.S.C. § 119(e) from U.S. Provisional Patent Application Number 63/110,548 filed on November 6, 2020, which is incorporated by reference herein in its entirety.

Field

[0002] The present disclosure relates generally to substrates and more particularly to substrates with improved electrostatic performance.

Background

[0003] Thin glass substrates are commonly utilized in flat panel display (FPD) devices such as liquid crystal display (LCD) and organic light emitting diode (OLED) displays. Substrates used in FPD devices generally have a functional A-side surface on which the thin- film transistors are fabricated and a non-functional backside or B-side surface which opposes the A-side surface. During manufacture of the FPD device, the B-side surface of the glass substrate may come into contact with conveyance and handling equipment of various materials, such as metals, ceramics, polymeric materials and the like. The interaction between the substrate and these materials often results in charging through the triboelectric effect or contact electrification. As a result, charge is transferred to the glass surface and can be accumulated on the substrate. As charge accumulates on the surface of the glass substrate, the surface voltage of the glass substrate also changes.

[0004] Electrostatic charging (ESC) of B-side surfaces of glass substrates used in FPD devices may degrade the performance of the glass substrate and/or damage the glass substrate. For example, electrostatic charging of the B-side surface may cause gate damage to thin film transistor (TFT) devices deposited on the A-side surface of the glass substrate through dielectric breakdown or electric field induced charging. Moreover, charging of the B-side surface of the glass substrate may attract particles, such as dust or other particulate debris, which may damage the glass substrate or degrade the surface quality of the glass substrate. In either circumstance, electrostatic charging of the glass substrate may decrease FPD device manufacturing yields thereby increasing the overall cost of the manufacturing process. [0005] Further, frictional contact between the glass substrate and handling and/or conveyance equipment may cause such equipment to wear, thereby reducing the service life of the equipment. Repair or replacement of worn equipment results in process down-time, decreasing manufacturing yields and increasing the overall costs of the FPD device manufacturing process.

[0006] Accordingly, a need exists for glass substrate processing methods that mitigate the generation of charge and decrease the friction between the glass substrates and equipment utilized in the manufacture of FPD devices.

SUMMARY

[0007] Embodiments disclosed herein include a substrate. The substrate includes a first major surface and an opposing second major surface extending in a generally parallel direction to the first major surface. The substrate also includes a glass sheet and a deposition layer extending between the glass sheet and the second major surface. The deposition layer includes inorganic particles and imparts a surface roughness on the second major surface of the substrate ranging from about 0.4 nanometers to about 50 nanometers.

[0008] Embodiments disclosed herein also include a method of making a substrate. The method includes depositing a deposition layer on a glass sheet. The deposition layer extends between the glass sheet and a second major surface of the substrate and the glass sheet extends between the deposition layer and a first major surface of the substrate. The first major surface extends in a generally parallel direction to the second major surface. The deposition layer includes inorganic particles and imparts a surface roughness on the second major surface of the substrate ranging from about 0.4 nanometers to about 50 nanometers.

[0009] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0010] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. l is a schematic view of an example fusion down draw glass making apparatus and process;

[0012] FIG. 2 is a perspective view of a glass sheet;

[0013] FIG. 3 is a side cutaway view of a glass sheet with a liquid dispersed deposition layer deposited thereon;

[0014] FIG. 4 is a side cutaway view of a glass sheet with a deposition layer deposited thereon;

[0015] FIG. 5 is a side cutaway view of a lift testing apparatus in a first stage of operation;

[0016] FIG. 6 is a side cutaway view of a lift testing apparatus in a second stage of operation; and

[0017] FIG. 7 is a side cutaway view of a lift testing apparatus in a third stage of operation.

DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0019] Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0020] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation. [0021] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0022] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0023] As used herein, the term “surface roughness” refers to the measured roughness on a major surface of a substrate as determined by the Surface Roughness Measurement Technique as described herein.

[0024] As used herein, the term “electrostatic charge” refers to the measured charge on a major surface of a substrate as determined by the Surface Voltage Measurement Technique as described herein.

[0025] Shown in FIG. 1 is an exemplary glass manufacturing apparatus 10. In some examples, the glass manufacturing apparatus 10 can comprise a glass melting furnace 12 that can include a melting vessel 14. In addition to melting vessel 14, glass melting furnace 12 can optionally include one or more additional components such as heating elements (e.g., combustion burners or electrodes) that heat raw materials and convert the raw materials into molten glass. In further examples, glass melting furnace 12 may include thermal management devices (e.g., insulation components) that reduce heat lost from a vicinity of the melting vessel. In still further examples, glass melting furnace 12 may include electronic devices and/or electromechanical devices that facilitate melting of the raw materials into a glass melt. Still further, glass melting furnace 12 may include support structures (e.g., support chassis, support member, etc.) or other components. [0026] Glass melting vessel 14 is typically comprised of refractory material, such as a refractory ceramic material, for example a refractory ceramic material comprising alumina or zirconia. In some examples glass melting vessel 14 may be constructed from refractory ceramic bricks. Specific embodiments of glass melting vessel 14 will be described in more detail below.

[0027] In some examples, the glass melting furnace may be incorporated as a component of a glass manufacturing apparatus to fabricate a glass sheet, for example a glass ribbon of a continuous length. In some examples, the glass melting furnace of the disclosure may be incorporated as a component of a glass manufacturing apparatus comprising a slot draw apparatus, a float bath apparatus, a down-draw apparatus such as a fusion process, an up- draw apparatus, a press-rolling apparatus, a tube drawing apparatus or any other glass manufacturing apparatus that would benefit from the aspects disclosed herein. By way of example, FIG. 1 schematically illustrates glass melting furnace 12 as a component of a fusion down-draw glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into individual glass sheets.

[0028] The glass manufacturing apparatus 10 (e.g., fusion down-draw apparatus 10) can optionally include an upstream glass manufacturing apparatus 16 that is positioned upstream relative to glass melting vessel 14. In some examples, a portion of, or the entire upstream glass manufacturing apparatus 16, may be incorporated as part of the glass melting furnace 12.

[0029] As shown in the illustrated example, the upstream glass manufacturing apparatus 16 can include a storage bin 18, a raw material delivery device 20 and a motor 22 connected to the raw material delivery device. Storage bin 18 may be configured to store a quantity of raw materials 24 that can be fed into melting vessel 14 of glass melting furnace 12, as indicated by arrow 26. Raw materials 24 typically comprise one or more glass forming metal oxides and one or more modifying agents. In some examples, raw material delivery device 20 can be powered by motor 22 such that raw material delivery device 20 delivers a predetermined amount of raw materials 24 from the storage bin 18 to melting vessel 14. In further examples, motor 22 can power raw material delivery device 20 to introduce raw materials 24 at a controlled rate based on a level of molten glass sensed downstream from melting vessel 14. Raw materials 24 within melting vessel 14 can thereafter be heated to form molten glass 28.

[0030] Glass manufacturing apparatus 10 can also optionally include a downstream glass manufacturing apparatus 30 positioned downstream relative to glass melting furnace 12. In some examples, a portion of downstream glass manufacturing apparatus 30 may be incorporated as part of glass melting furnace 12. In some instances, first connecting conduit 32 discussed below, or other portions of the downstream glass manufacturing apparatus 30, may be incorporated as part of glass melting furnace 12. Elements of the downstream glass manufacturing apparatus, including first connecting conduit 32, may be formed from a precious metal. Suitable precious metals include platinum group metals selected from the group of metals consisting of platinum, iridium, rhodium, osmium, ruthenium and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed from a platinum-rhodium alloy including from about 70 to about 90% by weight platinum and about 10% to about 30% by weight rhodium. However, other suitable metals can include molybdenum, palladium, rhenium, tantalum, titanium, tungsten and alloys thereof.

[0031] Downstream glass manufacturing apparatus 30 can include a first conditioning (i.e., processing) vessel, such as fining vessel 34, located downstream from melting vessel 14 and coupled to melting vessel 14 by way of the above-referenced first connecting conduit 32. In some examples, molten glass 28 may be gravity fed from melting vessel 14 to fining vessel 34 by way of first connecting conduit 32. For instance, gravity may cause molten glass 28 to pass through an interior pathway of first connecting conduit 32 from melting vessel 14 to fining vessel 34. It should be understood, however, that other conditioning vessels may be positioned downstream of melting vessel 14, for example between melting vessel 14 and fining vessel 34. In some embodiments, a conditioning vessel may be employed between the melting vessel and the fining vessel wherein molten glass from a primary melting vessel is further heated to continue the melting process, or cooled to a temperature lower than the temperature of the molten glass in the melting vessel before entering the fining vessel.

[0032] Bubbles may be removed from molten glass 28 within fining vessel 34 by various techniques. For example, raw materials 24 may include multivalent compounds (i.e. fining agents) such as tin oxide that, when heated, undergo a chemical reduction reaction and release oxygen. Other suitable fining agents include without limitation arsenic, antimony, iron and cerium. Fining vessel 34 is heated to a temperature greater than the melting vessel temperature, thereby heating the molten glass and the fining agent. Oxygen bubbles produced by the temperature-induced chemical reduction of the fining agent(s) rise through the molten glass within the fining vessel, wherein gases in the molten glass produced in the melting furnace can diffuse or coalesce into the oxygen bubbles produced by the fining agent. The enlarged gas bubbles can then rise to a free surface of the molten glass in the fining vessel and thereafter be vented out of the fining vessel. The oxygen bubbles can further induce mechanical mixing of the molten glass in the fining vessel.

[0033] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as a mixing vessel 36 for mixing the molten glass. Mixing vessel 36 may be located downstream from the fining vessel 34. Mixing vessel 36 can be used to provide a homogenous glass melt composition, thereby reducing cords of chemical or thermal inhomogeneity that may otherwise exist within the fined molten glass exiting the fining vessel. As shown, fining vessel 34 may be coupled to mixing vessel 36 by way of a second connecting conduit 38. In some examples, molten glass 28 may be gravity fed from the fining vessel 34 to mixing vessel 36 by way of second connecting conduit 38. For instance, gravity may cause molten glass 28 to pass through an interior pathway of second connecting conduit 38 from fining vessel 34 to mixing vessel 36. It should be noted that while mixing vessel 36 is shown downstream of fining vessel 34, mixing vessel 36 may be positioned upstream from fining vessel 34. In some embodiments, downstream glass manufacturing apparatus 30 may include multiple mixing vessels, for example a mixing vessel upstream from fining vessel 34 and a mixing vessel downstream from fining vessel 34. These multiple mixing vessels may be of the same design, or they may be of different designs.

[0034] Downstream glass manufacturing apparatus 30 can further include another conditioning vessel such as delivery vessel 40 that may be located downstream from mixing vessel 36. Delivery vessel 40 may condition molten glass 28 to be fed into a downstream forming device. For instance, delivery vessel 40 can act as an accumulator and/or flow controller to adjust and/or provide a consistent flow of molten glass 28 to forming body 42 by way of exit conduit 44. As shown, mixing vessel 36 may be coupled to delivery vessel 40 by way of third connecting conduit 46. In some examples, molten glass 28 may be gravity fed from mixing vessel 36 to delivery vessel 40 by way of third connecting conduit 46. For instance, gravity may drive molten glass 28 through an interior pathway of third connecting conduit 46 from mixing vessel 36 to delivery vessel 40.

[0035] Downstream glass manufacturing apparatus 30 can further include forming apparatus 48 comprising the above-referenced forming body 42 and inlet conduit 50. Exit conduit 44 can be positioned to deliver molten glass 28 from delivery vessel 40 to inlet conduit 50 of forming apparatus 48. For example, exit conduit 44 may be nested within and spaced apart from an inner surface of inlet conduit 50, thereby providing a free surface of molten glass positioned between the outer surface of exit conduit 44 and the inner surface of inlet conduit 50. Forming body 42 in a fusion down draw glass making apparatus can comprise a trough 52 positioned in an upper surface of the forming body and converging forming surfaces 54 that converge in a draw direction along a bottom edge 56 of the forming body. Molten glass delivered to the forming body trough via delivery vessel 40, exit conduit 44 and inlet conduit 50 overflows side walls of the trough and descends along the converging forming surfaces 54 as separate flows of molten glass. The separate flows of molten glass join below and along bottom edge 56 to produce a single ribbon of glass 58 that is drawn in a draw or flow direction 60 from bottom edge 56 by applying tension to the glass ribbon, such as by gravity, edge rolls 72 and pulling rolls 82, to control the dimensions of the glass ribbon as the glass cools and a viscosity of the glass increases. Accordingly, glass ribbon 58 goes through a visco-elastic transition and acquires mechanical properties that give the glass ribbon 58 stable dimensional characteristics. Glass ribbon 58 may, in some embodiments, be separated into individual glass sheets 62 by a glass separation apparatus 100 in an elastic region of the glass ribbon. A robot 64 may then transfer the individual glass sheets 62 to a conveyor system using gripping tool 65, whereupon the individual glass sheets may be further processed. [0036] FIG. 2 shows a perspective view of a glass sheet 62 having a first major surface 162, an opposing second major surface 164 extending in a generally parallel direction to the first major surface 162 (on the opposite side of the glass sheet 62 as the first major surface) and an edge surface 166 extending between the first major surface 162 and the second major surface 164 and extending in a generally perpendicular direction to the first and second major surfaces 162, 164.

[0037] FIG. 3 shows a side cutaway view of a glass sheet 62 with a liquid dispersed deposition layer 202 deposited thereon. Specifically, liquid dispersed deposition layer 202 is deposited on second major surface 164 of glass sheet 62 making a substrate precursor 62’. Liquid dispersed deposition layer 202 can be deposited on glass sheet 62 via disperser 300 according to methods known to persons having ordinary skill in the art including, but not limited to, at least one of spin coating, flow coating, or spray coating.

[0038] In certain exemplary embodiments, the deposition layer can be dispersed in water such that such that liquid dispersed deposition layer 202 comprises an aqueous dispersion. Deposition layer may also be dispersed in other liquids, including organic solvents, such as, for example, alcohols, aliphatic hydrocarbons, aromatic hydrocarbons, amines, esters, ethers, and/or ketones.

[0039] The weight percent (wt%) solids in the liquid dispersed deposition layer 202, while not limited, may, for example, range from about 0. lwt% to about 10wt%, such as from about 0.5wt% to about 5wt%, and further such as from about lwt% to about 3wt%. [0040] In certain exemplary embodiments, the liquid dispersed deposition layer 202 can comprise solid materials that comprise inorganic particles. Such particles may, for example, comprise at least one of an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica. Prior to being incorporated into the liquid dispersed deposition layer 202, such particles may, for example, comprise a Brunauer-Emmett-Teller (BET) specific surface area of at least about 100 square meters per gram, such as at least about 200 square meters per gram, and further such as at least about 300 square meters per gram, including from about 100 square meters per gram to about 500 square meters per gram, such as from about 200 square meters per gram to about 400 square meters per gram. BET specific surface area is determined by observing the physical adsorption of a gas on a surface of a solid and calculating the amount of adsorbate gas corresponding to a monomolecular layer on the surface using the Brunauer-Emmett-Teller (BET) adsorption isotherm equation as known to persons having ordinary skill in the art.

[0041] When the inorganic particles comprise an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica, they may be in amorphous or crystalline form. Examples of aluminum oxides and/or aluminum hydroxides that may be used in the liquid dispersed deposition layer 202 include, but are not limited to, amorphous aluminum oxide, alphaalumina, beta-alumina, gamma-alumina, gibbsite, bayerite, nordstrandite, boehmite, diaspore, or tohdite.

[0042] Subsequent to being deposited on glass sheet 62, liquid dispersed deposition layer 202 can be subjected to a drying step in order to evaporate the liquid such as, for example, by use of an air knife and/or elevated temperature drying as known to persons having ordinary skill in the art. For example, elevated temperature drying may be conducted at a temperature of at least about 100°C, such as at least about 200°C, such as from about 100°C to about 500°C for a time of at least about 10 seconds, such as from about 10 seconds to about 20 minutes. Air knife drying may, for example, be conducted for a time of at least about 30 seconds, such as from about 30 seconds to about 30 minutes.

[0043] FIG. 4 shows a side cutaway view of a glass sheet 62 with a deposition layer 204 deposited thereon. Specifically, deposition layer 204 is deposited on second major surface 164 of glass sheet 62 making a substrate 62”. Deposition layer 204 can, for example, be deposited onto second major surface 164 of glass sheet 62 as a result of drying of liquid dispersed deposition layer 202 as described above.

[0044] Deposition layer 204 can impart a surface roughness on the second major surface 206 of the substrate 62” ranging from about 0.4 nanometers to about 50 nanometers, such as from about 0.6 nanometers to about 20 nanometers, and further such as from about 0.8 nanometer to about 10 nanometers. Meanwhile, the first major surface 162 of the substrate 62” may, for example, have a surface roughness of less than about 0.5 nanometers, such as less than about 0.25 nanometers, including from about 0.05 nanometers to about 0.5 nanometers, such as from about 0.1 nanometers to about 0.25 nanometers.

[0045] The above-referenced surface roughness of second major surface 206 can at least in part be attributed to deposition layer 204 comprising inorganic particles. Such particles may, for example, comprise at least one of an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica. In addition, such particles may, for example, comprise a Brunauer-Emmett- Teller (BET) specific surface area of at least about 100 square meters per gram, such as at least about 200 square meters per gram, and further such as at least about 300 square meters per gram, including from about 100 square meters per gram to about 500 square meters per gram, such as from about 200 square meters per gram to about 400 square meters per gram. [0046] When the inorganic particles comprise an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica, they may be in amorphous or crystalline form. Examples of aluminum oxides and/or aluminum hydroxides that may be used in the deposition layer 204 include, but are not limited to, amorphous aluminum oxide, alpha-alumina, beta-alumina, gamma-alumina, gibbsite, bayerite, nordstrandite, boehmite, diaspore, or tohdite.

[0047] In certain exemplary embodiments, substrate 62” may be subjected to a washing step subsequent to the drying step described above. Specifically, at least one of first major surface 162 or second major surface 206 of substrate 62” may be washed with a liquid washing solution comprising a solvent, such as water or an organic solvent, and at least one solute. In certain exemplary embodiments, the solute may comprise at least one detergent and/or surfactant. In certain exemplary embodiments, the solvent comprises water (e.g., deionized water) and the solute comprises an alkali detergent, such as a detergent comprising at least one of potassium hydroxide (KOH) or sodium hydroxide (NaOH), commercial examples of which include Semi Clean KG and PK-LCG225X. In certain exemplary embodiments, the solute may be present in the solution at a weight percent of at least about 0.1%, including at least about 1%, such as from about 0.1% to about 10%, and further such as from about 1% to about 5%. In certain exemplary embodiments, the washing solution may be applied for a time of at least about 10 seconds, such as from about 10 seconds to about 10 minutes, at a temperature of at least about 20°C, such as from about 20°C to about 80°C. In addition, the washing solution may be applied according to methods known to persons having ordinary skill in the art including, but not limited to, spraying, brushing, and dipping. [0048] In certain exemplary embodiments, substrate 62” may be subjected to a drying step subsequent to the washing step described above. For example, following the washing step, substrate 62” may be dried by use of an air knife and/or elevated temperature drying as known to persons having ordinary skill in the art. For example, elevated temperature drying may be conducted at a temperature of at least about 100°C, such as at least about 200°C, such as from about 100°C to about 500°C for a time of at least about 10 seconds, such as from about 10 seconds to about 20 minutes. Air knife drying may, for example, be conducted for a time of at least about 30 seconds, such as from about 30 seconds to about 30 minutes.

[0049] In certain exemplary embodiments, substrate 62” may also be subjected to an etching step, such as an acid etching step. For example, a solution comprising an acid etchant such as hydrofluoric acid (HF) may be applied to at least second major surface 206 of substrate 62” according to methods known to persons having ordinary skill in the art such as spraying, dipping, or brushing, The acid etchant may, for example, be present in the solution of concentrations ranging from about 0.1 wt% to about 10wt% and applied at temperatures ranging from about 20°C to about 60°C for a time ranging from about 10 seconds to about 10 minutes.

[0050] Embodiments disclosed herein include those in which an etching step does not significantly affect the surface roughness of the second major surface 206 of substrate 62”. For example, subsequent to an etching step, the second major surface 206 of the substrate 62” can have a surface roughness ranging from about 0.4 nanometers to about 50 nanometers, such as from about 0.6 nanometers to about 20 nanometers, and further such as from about 0.8 nanometer to about 10 nanometers.

[0051] In certain exemplary embodiments, an absolute value of electrostatic charge (ESC) on the second major surface 206 of substrate 62” is less than about 200 volts (V), such as less than about 150 volts (V), and further such as less than 100 volts (V), and yet further such as less than about 50 volts (V), such as from about 0 volts (V) to about 200 volts (V), and further such as from about 1 volt (V) to about 150 volts (V), and yet further such as from about 2 volts (V) to about 100 volts (V), and still yet further such as from about 5 volts (V) to about 50 volts (V).

[0052] In certain exemplary embodiments, a total light transmission per 0.5 millimeter of thickness between the first major surface 162 and the second major surface 206 of substrate 62” in wavelength range between about 400 nanometers and about 850 nanometers is at least about 90%, such as at least about 95%, including from about 90% to about 99%. Total light transmission, as described herein, including the examples below, was determined by placing a 0.5 millimeter thick substrate sample in a Hitachi U-4000 Spectrophotometer to measure percent transmission (T%) in the wavelength range between about 400 and about 850 nanometers.

[0053] Embodiments disclosed herein can include those in which deposition layer 204 is not sintered. Embodiments disclosed herein can further include those in which deposition layer 204 is not melted. In addition, embodiments disclosed herein can include those in which deposition layer 204 is not compressively stressed. Embodiments disclosed herein can also include those in which deposition layer 204 does not contain substantial amounts (e.g., more than lwt%) of glass, metal, and/or organic compounds (e.g., binders, etc.). Additionally, embodiments disclosed herein can include those in which no wet or dry etching step (such as a wet or dry acid etching step) is performed on the glass sheet 62 prior application of the deposition layer 204.

[0054] In certain exemplary embodiments, a thickness of substrate 62” between the first major surface 162 and the second major surface 206 can be less than about 1 millimeter, such as less than about 0.5 millimeters, including between about 0.1 millimeters and about 1 millimeter, and further including between about 0.2 millimeters and about 0.5 millimeters. [0055] Embodiments disclosed herein may be used with a variety of glass compositions. Such compositions may, for example, include a glass composition, such as an alkali free glass composition, comprising 58-65 weight percent (wt%) SiCh, 14-20wt% AI2O3, 8-12wt% B2O3, l-3wt% MgO, 5-10wt% CaO, and 0.5-2wt% SrO. Such compositions may also include a glass composition, such as an alkali free glass composition, comprising 58-65wt% SiCh, 16- 22wt% AI2O3, l-5wt% B2O3, l-4wt% MgO, 2-6wt% CaO, l-4wt% SrO, and 5-10wt% BaO. Such compositions may further include a glass composition, such as an alkali free glass composition, comprising 57-61wt% SiO2, 17-21wt% AI2O3, 5-8wt% B2O3, l-5wt% MgO, 3- 9wt% CaO, 0-6wt% SrO, and 0-7wt% BaO. Such compositions may additionally include a glass composition, such as an alkali containing glass composition, comprising 55-72wt% SiO₂, 12-24wt% AI2O3, 10-18wt% Na₂O, 0-10wt% B2O3, 0-5wt% K₂O, 0-5wt% MgO, and 0- 5wt% CaO, which, in certain embodiments, may also include l-5wt% K2O and l-5wt% MgO.

[0056] Surface Roughness Measurement Technique

[0057] As described herein, including the examples below, surface roughness refers to atomic force microscopy roughness (AFM Ra) analysis measured using a Hitachi High-Tech AFM5400L. For each sample analyzed, a surface morphology image of AFM was scanned with Dynamic Force Mode (DFM) wherein cantilever SI-DF20P2 (spring constant=9N/m, resonance frequency: 100-200kHz, radius of tip: 7nm, tip height: Mum, lever length: 160um, lever width: 40um, lever thickness: 3.5um) was used. For each sample analyzed, a soft x-ray irradiated the substrate surface during the measurement using the following analytical parameters: Integral gain (0.2), Proportional gain (0.05), Z limit (500nm), Scanning area (lOum X lOum), Image quality X -axis (256) and Y-axis (256). The difference (P-V value) between the tallest “peak” and the deepest “valley” in the surface was also obtained.

[0058] Surface Voltage Measurement Technique

[0059] Electrostatic charge (ESC) on the second major surface of substrates as described herein, including the examples below, was determined by placing a substrate sample in a lift testing apparatus, as shown schematically in FIGS. 5-7. Specifically, as shown in FIG. 5, in a first stage of operation, an approximately 10 x 10 cm² substrate sample 62” is placed on three lift pins, 408a, 408b, and 408c, of the lift testing apparatus 400 so as to situate the sample about 30 millimeters above an anodized aluminum table 404. During this stage, an ionizer 410 treats the air gap between the second major surface of the substrate sample 62” and the table for about 30 seconds. Next, in a second stage of operation, as shown in FIG. 6, the three lift pins, 408a, 408b, and 408c, go down so that the second major surface of the substrate sample 62” contacts the table 404 and a vacuum 406 is turned on between the table 404 and substrate sample 62” for about 70 seconds. Next, in a third stage of operation, as shown in FIG. 7, the vacuum 406 is turned off and the substrate sample 62” is raised by the three lift pins, 408a, 408b, and 408c, and monitored for about 30 seconds by a Hanwa electrostatic force microscometer (ESFM) 402 to determine the electrostatic charge (ESC) in volts (V). During this stage, the gap between the first major surface of the substrate sample 62” and the ESFM 402 is about 10 millimeters and the gap between the second major surface of the substrate sample 62” and the table 404 is about 30 millimeters.

[0060] Examples

[0061] Embodiments disclosed herein will be further described with reference to the following non-limiting examples.

[0062] Example 1 :

[0063] Amorphous aluminum oxide particles having a BET specific surface area of about 300 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 1,000 rpm. The surface was then dried at about 200°C for about 15 seconds. The resulting substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.4%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 11.4 nanometers and the P-V value was measured to be about 209 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about +49 V. As a TFT process simulation, the substrate was then heated at about 590°C for about 30 minutes, after which measured ESC between the coated major surface and the lift testing apparatus was about -9 V. Next, as a further TFT process simulation, the substrate was dipped in an aqueous solution comprising about lwt% HF at about 23 °C for about 45 seconds after which measured ESC between the coated major surface and the lift testing apparatus was about +69V.

[0064] Example 2:

[0065] Boehmite particles having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 1,000 rpm. The surface was then dried at about 200°C for about 15 seconds. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 60 seconds, rinsed by deionized (DI) water at about 40°C for about 60 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.6%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 6.37 nanometers and the P-V value was measured to be about 166 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about -42 V. As a TFT process simulation, the substrate was then heated at about 590°C for about 30 minutes, after which measured ESC between the coated major surface and the lift testing apparatus was about -I V. Next, as a further TFT process simulation, the substrate was dipped in an aqueous solution comprising about lwt% HF at about 23 °C for about 45 seconds after which measured ESC between the coated major surface and the lift testing apparatus was about +114V.

[0066] Example 3 :

[0067] Boehmite particles having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 3 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 4,000 rpm. The surface was then dried at about 150°C for about 15 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 60 seconds, rinsed by deionized (DI) water at about 40°C for about 60 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.4%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 7.4 nanometers and the P-V value was measured to be about 99 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about -I V.

[0068] Example 4:

[0069] Amorphous aluminum oxide particles having a BET specific surface area of about 300 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 2,000 rpm. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.3%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 11.0 nanometers and the P-V value was measured to be about 193 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about +52 V.

[0070] Example 5:

[0071] Boehmite particles having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 2,000 rpm. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.5%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 4.6 nanometers and the P-V value was measured to be about 166 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about +19 V.

[0072] Example 6:

[0073] Amorphous aluminum oxide particles having a BET specific surface area of about 300 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a flow coater. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.4%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 15.9 nanometers and the P-V value was measured to be about 253 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about +106 V.

[0074] Example 7:

[0075] Boehmite particles having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a flow coater. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.3%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 8.1 nanometers and the P-V value was measured to be about 105 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers.

Measured ESC between the coated major surface and the lift testing apparatus was about -26 V.

[0076] Example 8:

[0077] Amorphous silicon oxide (colloidal silica) particles having a BET specific surface area of about 110 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 2,000 rpm. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.5%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 1.5 nanometers and the P-V value was measured to be about 74 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about -21 V.

[0078] Example 9:

[0079] A 70:30 wt% ratio mixture of boehmite and Amorphous silicon oxide (colloidal silica) each having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 1 wt% solids and applied to a major surface of Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters via a spin coater rotating at about 2,000 rpm. The surface was then dried with an air knife at room temperature for about 10 minutes. The resulting substrate was then washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 90 seconds, rinsed by deionized (DI) water at about 40°C for about 90 seconds, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.7%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 13.6 nanometers and the P-V value was measured to be about 162 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about +73 V. [0080] Example 10:

[0081] Boehmite particles having a BET specific surface area of about 220 m²/g were combined with water to create an aqueous dispersion of about 0.2 wt% solids and applied to a major surface of Coming Lotus™ NXT glass having a thickness of about 0.5 millimeters via a flow coater. After the aqueous dispersion was drained by sheet inclination for 20 seconds, the resulting substrate was then washed with an aqueous solution containing 4% Parker 225X detergent at about 50°C for about 10 minutes, rinsed by deionized (DI) water at about 40°C for about 10 minutes, and then dried in an oven at about 150°C for about 20 minutes. The substrate exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.7%. Surface roughness (AFM Ra) on the coated major surface was measured to be about 0.50 nanometers and the P-V value was measured to be about 17 nanometers. In contrast, surface roughness on the uncoated opposing major surface was about 0.2 nanometers. Measured ESC between the coated major surface and the lift testing apparatus was about -94 V.

[0082] Comparative example:

[0083] Corning Lotus™ NXT glass having a thickness of about 0.5 millimeters was washed with an aqueous solution containing 1% Parker 225X detergent at about 40°C for about 20 minutes, rinsed by deionized (DI) water at about 40°C for about 20 minutes, and then dried in an oven at about 150°C for about 20 minutes. The glass exhibited a total light transmission between its major surfaces in wavelength range between about 400 nanometers and about 850 nanometers of about 91.8%. Surface roughness (AFM Ra) on both major surfaces was measured to be about 0.2 nanometers and the P-V value was measured to be about 16 nanometers. Measured ESC between the glass major surface and the lift testing apparatus was about -350 V.

[0084] Embodiments disclosed herein can result in substantial surface voltage reduction of glass substrates, which can, in turn, enable reduced gate damage to TFT devices deposited on the A-side surface of the glass substrate, reduction of particles and debris on the B-side surface of the glass substrate, increase in FPD device manufacturing yields, and increase in service life of glass substrate handling and/or conveyance equipment.

[0085] Embodiments disclosed herein also include electronic devices comprising any of the substrates disclosed herein.

[0086] While the above embodiments have been described with reference to a fusion down draw process, it is to be understood that such embodiments are also applicable to other glass forming processes, such as float processes, slot draw processes, up-draw processes, tube drawing processes, and press-rolling processes.

[0087] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiment of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A sub strate compri sing : a first major surface and an opposing second major surface extending in a generally parallel direction to the first major surface; a glass sheet and a deposition layer extending between the glass sheet and the second major surface, the deposition layer comprising inorganic particles and imparting a surface roughness on the second major surface of the substrate ranging from about 0.4 nanometers to about 50 nanometers.

2. The substrate of claim 1, wherein the first major surface has a surface roughness of less than about 0.5 nanometers.

3. The substrate of claim 1, wherein the inorganic particles comprise a Brunauer-

Emmett-Teller (BET) specific surface area of at least about 100 square meters per gram.

4. The substrate of claim 3, wherein the inorganic particles comprise at least one of an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica.

5. The substrate of claim 1, wherein a total light transmission per 0.5 millimeter of thickness between the first major surface and the second major surface in wavelength range between about 400 nanometers and about 850 nanometers is at least about 90%.

6. The substrate of claim 1, wherein an absolute value of electrostatic charge

(ESC) on the second major surface is less than about 200 volts (V).

7. The substrate of claim 1, wherein a substrate thickness between the first major surface and the second major surface is between about 0.1 millimeters and about 1 millimeter. The substrate of claim 1, wherein the glass sheet comprises an alkali free glass composition comprising 58-65wt% SiCh, 14-20wt% AI2O3, 8-12wt% B2O3, l-3wt% MgO, 5-10wt% CaO, and 0.5-2wt% SrO. The substrate of claim 1, wherein the glass sheet comprises an alkali free glass composition comprising 58-65wt% SiCh, 16-22wt% AI2O3, l-5wt% B2O3, l-4wt% MgO, 2-6wt% CaO, l-4wt% SrO, and 5-10wt% BaO. The substrate of claim 1, wherein the glass sheet comprises an alkali free glass composition comprising 57-6 lwt% SiO2, 17-21wt% AI2O3, 5-8wt% B2O3, l-5wt% MgO, 3-9wt% CaO, 0-6wt% SrO, and 0-7wt% BaO. The substrate of claim 1, wherein the glass sheet comprises a glass composition comprising 55-72wt% SiO2, 12-24wt% AI2O3, 10-18wt% Na2O, 0-10wt% B2O3, 0-5 wt% K2O, 0-5 wt% MgO, and 0-5 wt% CaO, 1- 5wt% K2O, and l-5wt% MgO. An electronic device comprising the substrate of claim 1. A method of making a substrate comprising: depositing a deposition layer on a glass sheet, the deposition layer extending between the glass sheet and a second major surface of the substrate and the glass sheet extending between the deposition layer and a first major surface of the substrate, the first major surface extending in a generally parallel direction to the second major surface and the deposition layer comprising inorganic particles and imparting a surface roughness on the second major surface of the substrate ranging from about 0.4 nanometers to about 50 nanometers. The method of claim 13, wherein the method further comprises forming the glass sheet from molten glass. The method of claim 13, wherein the deposition layer is deposited on the glass sheet in a liquid dispersion. method of claim 15, wherein the liquid dispersion is deposited on the glass sheet by at least one of spin coating, flow coating, or spray coating. method of claim 15, wherein the liquid dispersion is subjected to a drying step subsequent to being deposited on the glass sheet. method of claim 17, wherein the substrate is subjected to a washing step subsequent to the drying step. method of claim 13, wherein the inorganic particles comprise a Brunauer-

Emmett-Teller (BET) specific surface area of at least about 100 square meters per gram. method of claim 19, wherein the inorganic particles comprise at least one of an aluminum oxide, an aluminum hydroxide, and/or a colloidal silica.